A two-intermediate model for imidazole-promoted peroxyoxalate chemiluminescence

A mechanism is proposed for imidazole-catalysed peroxyoxalate chemiluminescence. The reaction model includes a sequential formation of 1-aroxalylimidazole and 1,1'-oxalyldiimidazole as light-producing reaction intermediates. The suggestion is supported by the kinetic data obtained for the reaction of imidazole with bis(4-nitrophenyl) oxalate and on the recently reported ability of 1,1'-oxalyldiimidazole to function as an efficient chemiluminescence reagent. The relative contributions of different catalytic pathways and hydrolytic side-reactions are discussed.